A conserved motif in Argonaute-interacting proteins mediates functional interactions through the Argonaute PIWI domain
A conserved motif in Argonaute-interacting proteins mediates functional interactions through the Argonaute PIWI domain
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DOI：
10.1038/nsmb1302
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发表时间：
2007-10-01
影响因子：
16.8
通讯作者：
Ladurner, Andreas G.
中科院分区：
文献类型：
--
作者：
Till, Susanne;Lejeune, Erwan;Ladurner, Andreas G.
Argonaute（Ago）蛋白通过小RNA介导核酸靶标的沉默。在裂殖酵母中，Ago1、Tas3和Chp1组装成RITS复合物，该复合物使着丝粒附近的转录沉默。在这里，我们描述了Tas3内的重复基序，称为'Argonaute钩'，这是保守的从酵母到人类，并通过其PIWI结构域在体外和体内结合Ago蛋白。基序中关键残基的定点突变破坏了Ago结合和体内异染色质沉默。出乎意料的是，直接结合Ago钩需要结合短干扰RNA引导链的5'端的PIWI结构域口袋。此外，野生型而非突变型Ago钩肽解抑制靶信使RNA的微RNA介导的翻译沉默。因此，含有保守的Ago钩的蛋白质可能是RNA干扰中效应复合物的重要调控组分。
Argonaute (Ago) proteins mediate silencing of nucleic acid targets by small RNAs. In fission yeast, Ago1, Tas3 and Chp1 assemble into a RITS complex, which silences transcription near centromeres. Here we describe a repetitive motif within Tas3, termed the 'Argonaute hook', that is conserved from yeast to humans and binds Ago proteins through their PIWI domains in vitro and in vivo. Site-directed mutation of key residues in the motif disrupts Ago binding and heterochromatic silencing in vivo. Unexpectedly, a PIWI domain pocket that binds the 5' end of the short interfering RNA guide strand is required for direct binding of the Ago hook. Moreover, wild-type but not mutant Ago hook peptides derepress microRNA-mediated translational silencing of a target messenger RNA. Proteins containing the conserved Ago hook may thus be important regulatory components of effector complexes in RNA interference.